docs: def _collectOffAxisPoints(self):
          """
              Return a dictionary with all off-axis locations.
          """
          offAxis = {}
          for l, (value, deltaName) in self.items():
              location = Location(l)
              name = location.isOnAxis()
              if name is None or name is False:
                  offAxis[l] = 1
          return list(offAxis.keys())